1. Field of the Invention
This invention relates to a pipe having a double flared end. More particularly, it relates to an improved construction of the double flared end of a metal pipe having a relatively small inside diameter not exceeding about 30 mm and a small wall thickness not exceeding about 2 mm, containing a resin or rubber tube fitted tightly therein, and adapted for conveying air or gas or a corrosive liquid in an automobile or any of various machines or apparatus.
2. Description of the Prior Art
A pipe assembly of the type to which this invention pertains is disclosed in Japanese Utility Model Application No. 36485/1983 filed on Mar. 14, 1983. It is shown in FIG. 2. It comprises a metal pipe 11 containing a resin or rubber tube 12 therein and having a double flared end 13 defined by a radially inward bend. This bend defines an inner wall portion 15 having an outer surface 14 defining a seat for a mating holder 20. The tube 12 has one end 12' held between the inner wall portion 15 and the outer wall portion of the double flared end 13. The double flared end 13 is held against the holder 20 by a nut 19.
As is obvious from FIG. 2, however, the inner wall portion 15 terminates in a radially inclined or conical plane. The inner wall portion 15 tends to spring back toward its original shape prior to bending and thereby fails to hold the end 12' of the tube 12 properly. When the flared end 13 is bent, the force applied thereto by punching tends to displace the tube 12 axially and thereby create a clearance 16 within the flared end 13. The flared end 13, thus, fails to hold the tube 12 properly. The clearance 16 often allows the fluid to reach the inner surface of the pipe 11 and corrode it.